javascript, acessing a json key stored in variable

Question

I've got the following code:

function valor_actual(moneda) { 
     var url="https://poloniex.com/public?command=returnTicker";
        var response = UrlFetchApp.fetch(url); 
        var dataAll = JSON.parse(response.getContentText()); 
        var dataSet = dataAll;
        var pair= "BTC_"+moneda
        return dataSet.pair.last; 
}

This code of couse is not working..

The moneda variable could have different values, for example, "VTC" or "AUR" or .... What i need is if moneda="AUR" return dataSet.BTC_AUR.last property and if moneda="SC" return dataSet.BTC_SC.last property, etc...

Regards,

Answer 1

Referring to these questions: How to convert string as object's field name in javascript ; Convert string value to object property name

Try changing your last line to: dataSet[pair].last;

As a side note, based off the code you have given the line: var dataSet = dataAll; is redundant. The names lead me to believe that dataSet is meant to be a subset of dataAll but as written dataSet is just a copy of dataAll. So your code can be simplified to:

function valor_actual(moneda) { 
     var url="https://poloniex.com/public?command=returnTicker";
        var response = UrlFetchApp.fetch(url); 
        var dataAll = JSON.parse(response.getContentText()); 
        var pair= "BTC_"+moneda
        return dataAll[pair].last; 
}